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PRI and Neuroplasticity

Posted by on 07/31/2014

PRI and Neuroplasticity

Recently I have read a few books that have helped me understand why PRI treatment is structured the way it is and why the results are so effective. “On Intelligence” by Jeff Hawkins and “The Brain That Changes Itself” by Norman Doidge explain the way our nervous system is organized and the plasticity that allows it to change. Our brains are plastic throughout life, this gives us the ability to learn new skills and change the way we currently do things. PRI uses neuroplasticity to create lasting changes in their patients by taking them through the four stages of learning.

During an evaluation a PRI practitioner identifies the pattern that the patient is in and then explains their findings to the patient. An important part of this is to help the patient understand that their right side and left side are different. For example, if a patient comes in with back pain they may be centered on their right leg when walking even during the left stance phase of gait. Additionally, their right arm may not swing like the left arm does when they walk. They are unaware of this so we help show them which leg is easier to balance on. We ask the patient to put one foot in front of the other with their hips shifted to the back leg and pick up their front foot. These are the positions of left and right midstance. With the example above, it would be easier for them to balance on their right leg rather than their left. They were in the unconscious incompetence stage before they became aware of it. After this, the patient would be provided exercises to help inhibit the muscles that are holding them in this right dominant pattern and facilitate other muscles to get them centered on their left side. The muscles are often facilitated in isolation. With the example patient, they could be given one exercise to turn on their left hamstring, one to turn on their left adductor, and another to turn on their right glute max. It may still be difficult for them to feel these muscles but they are aware of it, they are consciously incompetent. As time progresses so does the patient. They are put in more challenging positions such as standing and asked to feel their left adductor, their left glute med, and their left abdominal wall at the same time. When they can feel these muscles working together without much effort they are in the conscious competence stage of motor learning. As the patient progresses even further they begin to use these muscles during activity without even being aware of it. This will be seen by the clinician as the patient can now center over their left leg during left stance while both arms swing. The patient knows they have improved because they no longer have back pain. This is the final stage of learning, unconscious competence.

Understanding how the brain is structured and how it learns can help you structure a PRI program. Jeff Hawkins describes how the cortex of our brain is basically made up of six layers in a hierarchy. The higher levels of the hierarchy is where our attention is. We use these levels when we are challenged with things that require focus. Before riding a bike we don’t even know how bad we are at it, we are unconsciously incompetent. When we first begin to ride the bike we focus on everything in order to not fall but still fall often. We are consciously incompetent. As we get better at riding the bike we require less attention on all the little details but still focus some aspects, we are consciously competent and the skill is moving down the cortical hierarchy. Once we have mastered how to ride a bike we can do it while talking to others and not paying attention to what’s in front of us and we don’t fall, we are unconsciously competent. The mastered skill resides in the bottom of the cortical hierarchy and does not require our attention. A patient progressing through a PRI program goes through the same process as a kid learning to ride a bike! This happens due to how PRI exercises are progressed.

In Norman Doidge’s book he says “the key in developing exercises is to give the brain the right stimuli, in the right order, with the right timing to drive plastic change”, this is what PRI has the ability to do through graded exposure. Which exercises to prescribe, when to prescribe them, and when to progress them is determined by the results of the tests that we perform every visit. Muscles are facilitated in various positions often in an isolated way at first to make the patient aware of what they are doing which requires processing from the higher levels of the cortex, or attention. As the patient displays that they are progressing, as determined by our test results, these muscles are put in a position where they must work together like they should when we walk. This is done through integration which works on the principle that “neurons that wire together, fire together” as Doidge says throughout his book. An example of the exercises that help with integration are some of the ones done in standing. The standing exercises that involve the patient to feel their left adductor, left glute medius, and left abdominal wall are integrating, or wiring, the three muscles together to function in the left stance phase of gait. Initially, these type of exercises require the patient to be attentive and they are still using their higher cortical levels to complete the task. As the patient practices, the task moves down the cortical hierarchy. When they have become competent the muscles work together during gait without the patient being mindful of it. The brain has changed how the output, gait, is performed due to neuroplasticity.

Neuroplasticity is a dynamic process which needs repetition and reinforcement in order to create change. This is why patients are asked to do their exercises at least once a day in order to reinforce the inputs going into the system to create a better output of movement through graded exposure. As the system changes and learns less input is needed to keep the new output. For lasting changes to happen learning has to occur which requires plastic changes in the brain. Learning takes time and the correct timing of inputs to change the output.